Generally described, a gas turbine engine includes a combustor to ignite a mixture of fuel and air so as to produce combustion gases to drive a turbine. The combustor may include a number of fuel nozzles and a pressurized combustion zone surrounded by a liner, a flow sleeve, and an outer casing. The liner and the flow sleeve may define a cooling flow path therebetween. During operation, high pressure air may be discharged from a compressor into the combustor. A portion of the air may be mixed with fuel and ignited within the combustion chamber as described above. A further portion of the air may be channeled through the flow path for cooling the liner and other components. This process may be repeated by any number of combustors positioned in a circumferential array.
One or more radial penetrations may pass through the outer casing, the flow sleeve, and the liner of each combustor so as to interact with the combustion gases within the combustion chamber. These radial penetrations may include an igniter, pressure probes, flame detectors, and other types of components. The radial penetrations generally may be accompanied by different types of hardware to prevent or limit leakage out of the pressurized combustion chamber. The profile of such hardware within the flow path, however, generally has been relatively large so as to accommodate thermal growth. Such a large profile may generate wakes in the flow of air that may cause a non-uniform distribution of the air to the fuel nozzles or other fuel mixing component. The non-uniform distribution of air may result in flame instabilities and other types of combustion issues that may have an impact on overall efficiency.
There is thus a desire for an improved leakage control system for radial penetrations in a combustor. Preferably such a leakage control system may accommodate different types of radial penetrations while limiting leakage and limiting the creation of a non-uniform distribution of air in the cooling flow path for more efficient overall operation.